Sampling Flashcards
Sampling frame
Created to order people in the target population
Random sampling
All members have an equal chance of being selected e.g. picking names out of a hat
Systematic sampling
Every nth number of the target population is selected. Random to reduce bias
Stratified sampling
Where the sample reflects the proportion of the target population of which they wish to study.
Researchers identified different strata (sub groups), then proportions they for a fully representative sample
Opportunity sampling
Anyone from the target population that are available at the time and are willing to take part. May be people on the street or people with a certain medical diagnosis
Volunteer sampling
Participants select themselves to be part of the sample (self-selection). E.g. an advert placed on a notice board or online and willing participants get in contact
Strength of stratified sampling
Representative
Strength of opportunity and volunteer sampling
Take less time to find a sample than other methods
Weakness of volunteer sampling
Suffer from volunteer bias where participants may be highly motivated to take part and therefore differ from a typical member of the population
Weakness of opportunity sampling
Inevitably, biased by Hugh happens to be available at the time so not very representative
Weakness of opportunity sampling
Inevitably, biased by Hugh happens to be available at the time so not very representative
Weakness of random sampling
Time-consuming because it requires a list of names of all members of the population from which have been randomly selected and recruited. People selected may also refuse to take parts, resulting in a biased sample.
Strength of stratified sampling
Representative, because it is a proportional representation of sub groups
Weakness of stratified sampling
Subgroups identified must be randomly selected then contacted. This is very time-consuming and people may not agree to participate, giving a biased sample
